Motor control for door operation



July 31, 1956 J. OLIVER MOTOR CONTROL FOR DOOR OPERATION 2 Sheets-Sheet1 Filed March 9, 195-3 Hill Q INVENTUH J u SEPH L. ULIVER BY [W ATTDRNEY July 31., 1956 J.,IL. OLIVER 2,757,327

MOTOR CONTROL FOR DOOR OPERATION Filed March 9, 1953 2 Sheets-Sheet 2 INYEN TDR JOSEPH L. ULIVER ATTDRNET United States Patent MOTOR CONTROL F22 noon OPERATIGN Joseph L. @liver, Rochester, N. Y., assignor ofone-fourth to Francis V. Spronz, Rochester, N, Y.

Application March 9, 1953, Serial No. 341,212 10 Claims. (ill. 318-265)This invention relates to power mechanism for opening and closing garagedoors and the like, and more particularly to an automatic stop controltherefor.

in garage door installations of the motor driven type, it has been apractice to cut off the power when the door reaches its open or closedposition by limit switches operating in response to the door reachingcertain set end positions. Where a sprocket and chain drive is employed,it is usual for convenience to actuate limit switches by suitablyadjusted abutments carried by the chain. in such installations, it isnecessary to employ a chain drive, since a positive relationship betweenthe chain and door positions must be maintained. Such a system ofiers noprotection against obstructions which may move into the path of thedoor, or ice and snow accumulations which may prevent the door fromreaching its precise set end position.

The present invention is directed to a control for a door operated freeof fixed stops, the invention being directed to apparatus adapted tosense the door reaching an end of travel abutment, and act to cut offthe power. The apparatus is further adapted to permit immediate stoppageof movement of the door upon a preset increase in the resistance tomovement of the door, whereby its travel may be stopped at any point.The invention is further directed to a friction drive, wherein slippagedue to abnormal resistance to door movement cuts off the power andestablishes a circuit in readiness for reverse movement. The inventionis further directed to an effective safe control comprising few parts,sure of operation, economical to manufacture, and easy to install.

The above and other novel features of the invention will appear morefully hereinafter from the following detailed description when taken inconjunction with the accompanying drawings. It is expressly understoodthat the drawings are employed for purposes of illustration only and arenot designed as a definition of the limits of the invention, referencebeing had for this purpose to the appended claims.

in the drawings, wherein like reference characters indicate like parts:

Figure 1 is a prespective View of the motor drive and switch assembly;

Figure 2 is an axial sectional view taken through the clutch and camactuator;

Figure 3 is a transverse sectional view taken on the line 3-3 of Figure2, looking toward the left;

Fi ure 4 is a transverse sectional view taken on the line 4-4 of Figure2, looking toward the right;

Figure 5 is a fragmentary top elevational view of the keying fingers;

Figure 6 is a top fragmentary plan view of the switch actuating leverand actuating plate; and

Figure 7 is a circuit diagram utilized to control the motor operation.

Referring to Figure 1, there is shown a reversible motor 10, which maybe of the induction motor type, in which connections to the startingwinding are reversed for forward and reverse rotation. The motor isconnected to a reduction gear 12, which in turn drives a shaft 14 atrelatively low speed. The motor and reduction gear are mounted upon asuitable frame such as 16.

Referring to Figures 26, there will be seen mounted upon the shaft adrive sprocket 18 to which is affixed a friction clutch plate 26, as bywelding 22. The sprocket is connected by chains to the door opening andclosing mechanism in a manner which will be understood in the art. Thesprocket l8 and plate 20 are freely rotatable upon the shaft 14. Securedt0 the shaft 14 as by welding as at 24 is a clutch plate 26 having afriction facing 28, which facing frictionally engages the clutch plate2%. The friction lining 28 is secured to the clutch plate 26 by a seriesof rivets 29. The end of the shaft 14 is threaded as at 30 and providedwith adjustable locking nuts 32; and 34 which act through a spring 36mounted on the shaft 1 such spring being held in compression between thenut 34 and the sprocket 18. By adjustment of the nut 34, the pressurebetween the friction plate 20 and the lining 23 may be adjusted, so thata predetermined slipping torque is established between the sprocket l8.and the shaft 14.

The clutch plate 2 6 is provided with arcuate raised surfaces 33terminating at either side by short camming surfaces 40 and 42. Suchraised surfaces may be stamped in the plate 26 as will be wellunderstood in the art. Axially slidable and freely rotatable on theshaft 14 is a follower plate having projections 46, such projectionshaving riding surfaces 48 arranged on a circle of a diametersubstantially that of the diameter of the circle upon which the arcuatesurfaces 38 are formed. Such projections are as high or higher than theraised arcuate surfaces 38, so that the projections may engage the plate26 at all times. The disk 44 is provided on diametrically opposed sidesthereof with pairs of spaced right angle bent fingers 5t) and 51, theaxial portions 52 and 53 of which extend loosely on either side of asimilar finger 54 secured to the plate 20, such finger 54 having anaxially extending portion 55 extending between the axial portions 52 and53 of the fingers 50 and 51. The plate 44 is therefore constrained torotate with the sprocket 18, although it may freely move axially uponthe shaft 14. A relatively light spring 53 is arranged upon the shaft 14between the reduction gear box 12 and the disk 44, in order to urge thedisk 44- to the left as shown in Figure 2, so that projections 4% willride upon the raised cam surfaces 38 or the cams 4b and 42 or theintervening areas 39 between adjacent raised cam surfaces 38.

It will thus appear that so long as the sprocket 18 rotates with theshaft 14, the projections 48 of the plate 44 will ride upon the camsurfaces 38 or the intervening areas 39 of the plate 26 without relativerotation between the plates 26 or 44. Should, however, the sprocket 18be loaded by a torque exceeding that of the friction clutch driveadjustment, such sprocket will be retarded or stopped and rotaterelative to the shaft 14, causing the projections 45 to slide upon theplate 26, causing said projections either to ride off of the arcuatesurfaces 38 down the cam inclines do or 42 onto the intervening surfaces39, or conversely from the surfaces 39 and up the cam surfaces 40 and 42onto the raised arcuate surfaces 38. Such relative motion moves theplate 44 axially a slight distance upon the shaft 14, either against thespring 58 in one direction or in consequence of the pressure of spring58 in the other direction.

Mounted upon the reduction gear 12 is a lever 60 pivoted as at 62, suchlever having an arm 64 bearing against the plate 44. The other end ofthe lever 60 is provided with an arm 66 which engages a switch actuatinglever 68, such lever 68 being effective to actuate a switch '70 of thesingle pole double throw type, the switch being of the type generallyreferred to in the trade as a microswitch. When the disk 44 is in theposition shown in Figure 2, the switch 70 is thrown to one of its closedcircuit positions through the operation of the lever 60, and when thedisk moves to the left of the position in which it is shown in Figure 2,that is, to the position where the projections 48 ride upon theintervening areas 39, the switch is thrown to the other of its closedcircuit positions. The lever 60 is biased for counterclockwise rotationas seen in Figure 6, by a light spring 72.

Referring to the circuit diagram in Figure 7, there is shown theinduction motor 10, with its field winding 74 and its starting winding76, which generally includes a centrifugal switch. There is also shownthe switch 70 previously referred to, and also a manual single poleswitch 78, which switch, when momentarily closed, commences operation ofthe motor in one direction or the other, depending upon the position ofthe switch 70 and the particular circuit closed thereby. The motorderives its power from leads 80 and 82, and by reason of one or theother of the electromagnetic switches 84 and 86. Each of the switches 84and 86 are actuated by solenoids 88 and 90, and when one or the other isenergized, the switch so energized opens one circuit and closes fourcircuits. Such switch 84, for example, when energized, opens contacts92, and closes contacts 94, 96, 98, and 100. On the other hand, switch86, when energized, opens contacts 102, and closes contacts 104, 106,108, and 110.

Power for actuation of the switches 84 and 86 is derived from astep-down transformer 112, such transformer having a low voltagesecondary 114. Assuming switch 78 is momentarily closed, a circuit isestablished through contacts 92 and switch solenoid 90 and the lowercontacts 116 of switch 70, so that contacts 102 are opened, contacts104, 106, 108, and 110 are closed. Contacts 104, when closed, serve toestablish a hold-in circuit for maintaining energization of the solenoid90 when the switch 7 8 is opened, such circuit including the secondary114, contacts 104, contacts 92, solenoid 90, and switch 70 throughcontact 116. Contacts 106 serve to close a circuit between the line 82and the line 80 through the motor field 74, contacts 108 and 110 servingto close a circuit through the motor starting winding 76, such circuitderiving its power from the line 80 through lead 118 and from the line82 through lead 120.

When the motor starts, the sprocket 18 is driven slowly and drives thedoor toward an open or closed position. When the door reaches its closedposition, it is stopped by an abutment, whereupon the friction clutchformed by plates occurs, relative rotation takes place between plates20, 26 and 44, whereby the projections 48 ride from the raised surfaces38 to the intervening plate surfaces 39. This actuates the lever 60 andactuates switch 70 to open the contacts 116 and close such switchthrough the other contact 122. When the switch 70 is thus opened withrespect to contact 116, the solenoid 90 is de-energized, and thecontacts 104, 106, 108, and 110 are opened, and contacts 102 are closed.When the switch 78 is again manually closed for a brief period, solenoid88 is energized through a circuit including contacts 102 and contact 122of switch 70. Thereupon solenoid switch contacts 92 are opened, andcontacts 94, 96, 98, and 100 are closed.

Switch contacts 94 establish a hold-down circuit in the same manner asestablished previously by contacts 104. Contacts 96 close a circuit tothe motor field 74, and contacts 98 and 100 complete a circuit to themotor starting winding, such connection being reversed from theconnection established by contacts 108 and 110. Thus, the motor rotatesin the opposite direction, causing the sprocket 18 to rotate in theopposite direction,

and 26 is caused to slip. As soon as slippage moving the door toward itsother end position. When the door is stopped by suitable abutments or byobstruction, slippage again occurs on the clutch plates 20 and 26,causing relative rotation between plates 26 and 44. Such action causesthe projections 48 to ride up the cam surfaces 42 or 40 to the raisedarcuate surfaces 38, shifting the switch 70 back to the position shownin Figure 7.

It will be appreciated that the door may be stopped regardless ofdirection at any point along its path of travel if sufficient resistanceto its movement is applied to cause the clutch plates 20 and 26 to slip.Thus, should a door strike an object which might be damaged by continuedoperation'of the closing or opening movement, the door will instantlystop, and upon the next operation of the manual switch 78, such doorwill move in the reverse direction away from the obstruction. It will beappreciated that the spring 36 may have its tension adjusted, so thatthe clutch may slip upon the slightest overload or upon heavy overloadto suit conditions. It will further appear that the earns 40 or 42 areof relatively short arcuate length, so that when the motor current iscut off, the over-ride will assure suficient additional relativerotational movement between the plates 26 and 44 as to move theprojections 48 e'ther from the surfaces 39 to the raised surfaces 38, orvice versa, and sufficient to actuate switch 70. It can be readily seenthat the need for a sprocket and chain or positive drive is eliminated,so that while a sprocket is shown, yet an economical belt drive can beused, and that protection against motor overload is provided, since anyoverload instantly acts to cut the motor off.

While a single embodiment of the invention has been illustrated anddescribed, it is to be understood that the invention is not limitedthereto. As various changes in the construction and arrangement may bemade without departing from the spirit of the invention, as will beapparent to those skilled in the art, reference will be had to theappended claims for a definition of the limits of the invention.

What is claimed is:

1. In a power actuator for an overhead door or the like, a reversibleelectric motor, a reduction gear driven thereby having an output shaft,a drive member freely rotatable on said shaft, a friction clutch havinga predetermined slipping torque for coupling said drive member to saidshaft, whereby said shaft may rotate relative to said drive member uponsaid drive member resisting rotation in excess of said torque, and meansresponsive to relative rotation in either direction between said drivemember and shaft caused by exceeding said torque for de-energizing saidmotor.

2. In a power actuator for an overhead door or the like, a reversibleelectric motor, a reduction gear driven thereby having an output shaft,a drive member freely rotatable on said shaft, a friction clutch havinga predetermined slipping torque for coupling said drive member to saidshaft for rotation together until said torque is exceeded, a circuit forenergizing said motor for rotation in one direction, a circuit forenergizing said motor for opposite rotation, and means responsive to theslipping of said clutch and relative rotation between said shaft andmember for de-energizing one or the other of said circuits and preparingthe remaining circuit for energization.

3. In a power actuator for an overhead door or the like, a reversiblemotor, a reduction gear driven thereby, and having an output shaft, adrive wheel freely mounted on said shaft, a friction driving facethereon, a disk secured to said shaft, and having a friction faceengaging said driving face under a predetermined pressure wherebyslippage is prevented below a predetermined torque, said disk having onits opposite face alternate arcuate axially staggered surfaces, saidalternate surfaces lying in spaced planes, a follower disk freelyrotatable and axially movable on said shaft and having engaging meansadapted to ride on either one set of said alternate arcuate surfaces orthe other, means for constraining said follower disk to rotate with saiddrive wheel, and means responsive to axial movement of said followerdisk for stopping said motor.

4. In a power actuator for an overhead door or the like, a reversiblemotor, a reduction gear driven thereby, and having an output shaft, adrive wheel freely mounted on said shaft, a friction driving facethereon, a disk secured to said shaft, and having a friction faceengaging said driving face, means for engaging said faces under apredetermined pressure whereby slippage occurs only after apredetermined torque is exceeded, said disk having on its opposite facealternate arcuate axially staggered surfaces, said alternate surfaceslying in spaced planes, a follower disk freely rotatable and axiallymovable on said shaft and having engaging means adapted to ride oneither one set of said alternate arcuate surfaces or the other, meansfor constraining said follower disk to rotate with said drive wheel,said engaging means being adapted to move said follower disk axiallyfrom one position to the other upon relative rotation between saidfriction disk and wheel when said predetermined torque is exceeded, andmeans responsive to axial movement of said follower disk for stoppingsaid motor.

5. In a power actuator for an overhead door, a reversible motor, areduction gear driven thereby, and having an output shaft, a drive wheeifreely mounted on said shaft, a friction driving face thereon, a disksecured to said shaft, and having a friction face engaging said drivingface, means for engaging said faces under a predetermined pressurewhereby slippage occurs only after a predetermined torque is exceeded,said disk having on its opposite face alternate arcuate axiallystaggered surfaces, said alternate surfaces lying in spaced planes, afollower disk freely rotatable and axially movable on said shaft andhaving engaging means adapted to ride on either one set of saidalternate arcuate surfaces or the other, means for constraining saidfollower disk to rotate with said drive wheel, said engaging means beingadapted to move said follower disk axially from one position to theother upon relative rotation between said friction disk and wheel whensaid predetermined torque is exceeded, a lever engaging said followerdisk and adapted to be rocked by axial movement thereof from oneposition to the other, and a switch actuated by said lever adapted tode-energize said motor upon axial movement of the follower disk.

6. In a power actuator for an overhead door, a reversible motor, areduction gear driven thereby, and having an output shaft, a drive wheelfreely mounted on said shaft, a friction driving face thereon, a disksecured to said shaft, and having a friction face engaging said drivingface, means for engaging said faces under a predetermined pressurewhereby slippage occurs only after a predetermined torque is exceeded,said disk having on its opposite face alternate arcuate axiallystaggered sur faces, said alternate surfaces lying in spaced planes, afollower disk freely rotatable and axially movable on said shaft andhaving engaging means adapted to ride on either one set of saidalternate arcuate surfaces or the other, means for constraining saidfollower disk to rotate with said drive wheel, said engaging means beingadapted to move said follower disk axially from one position to theother upon relative rotation between said friction disk and wheel whensaid predetermined torque is exceeded, a lever engaging said followerdisk and adapted to be rocked by axial movement thereof from oneposition to the other, a circuit for energizing said motor for rotationin one direction, a circuit for energizing said motor for oppositerotation, a switch actuated by said lever and adapted to open one or theother of said circuits and prepare the remaining circuit forenergization.

7. In a power actuator for an overhead door, a reversible motor, areduction gear driven thereby and having an output shaft, a drive wheelfreely rotatably mounted on said shaft having a friction driving face, afriction disk secured to said shaft having a face in engagement withsaid driving face, means maintaining axial pressure between said facesto establish a predetermined maximum driving torque which, whenexceeded, results in slippage, said friction disk having on its oppositeface a plurality of alternate arcuate surfaces axially staggered withadjacent arcuate surfaces connected by axial camming surfaces, saidsurfaces comprising two sets lying in axially spaced planes, a followerdisk axially movable on said t having following means adapted to engageone at a time one set or the other of said arcuate faces, said diskbeing keyed for rotation with said drive wheel whereby upon frictionslippage between said wheel and friction disk, said following means iscammed from one set of arcuate surfaces to the other and moved axially,means responsive to axial movement of said disk for stopping said motor.

8. in a power actuator for an overhead door, a reversible motor, areduction gear driven thereby and having an output shaft, a drive wheelfreely rotatably mounted on said shaft having a friction driving face, afriction disk secured to said shaft having a face in engagement withsaid driving face, means maintaining axial pressure between said facesto establish a predetermined driving torque, said friction disk havingon its opposite face a plurality of alternate arcuate surfaces axiallystaggered with adjacent arcuate surfaces connected by axial cammingsurfaces, said surfaces comprising two sets lying in axially spacedplanes, a follower disk axially movable on said shaft having followingmeans adapted to engage one at a time one set or the other of saidarcuate faces, said disk being keyed for rotation with said drive wheelwhereby upon friction slippage between said wheel and friction disk,said following means is cammed from one set of arcuate surfaces to theother and moved axially, a lever engaging said disk and adapted to berocked by axial movement thereof, and a switch actuated by said leveradapted to de-energize said motor upon axial movement of the disk.

9. in a power actuator for an overhead door, a reversible motor, areduction gear driven thereby and having an output shaft, a drive wheelfreely rotatably mounted on said shaft having a friction driving face, afriction disk secured to said shaft having a face in engagement withsaid driving face, means maintaining axial pressure between said facesto establish a predetermined driving torque, said friction disk havingon its opposite face a plurality of alternate arcuate surfaces axiallystaggered with adjacent arcuate surfaces connected by axial camrninsurfaces, said surfaces comprising two sets lying in axially spacedplanes, a follower disk axially movable on said shaft having followingmeans adapted to engage one at a time one set or the other of saidarcuate faces, said disk being keyed for rotation with said drive wheelwhereby upon friction slippage between said wheel and friction disk,said following means is cammed from one et of arcuate surfaces to theother and moved axially, a lever engaging said disk and adapted to berocked by axial movement thereof, a circuit for energizing said motorfor rotation in one direction, a circuit for energizing said motor foropposite rotation, a switch actuated by said lever and adapted to openone or the other of said circuits and prepare the remaining circuit forenergization.

10. In a power actuator for an overhead door, a reversible motor, areduction gear driven thereby and having an output shaft, a drive wheelfreely rotatably mounted on said shaft having a friction driving face, afriction disk secured to said shaft having a face in engagement withsaid driving face, means maintaining axial pressure between said facesto establish a predetermined driving torque, said friction disk havingon its opposite face a plurality of alternate arcuate surfaces axiallystaggered with adjacent arcuate surfaces connected by axial cammingsurfaces, said surfaces comprising two sets lying in axially spacedergizing said motor for opposite rotation,

planes, a follower disk axially movable on said shaft having followingmeans adapted to engage one at a time one set or the other of saidarcuate faces, said disk being keyed for rotation with said drive wheelwhereby upon friction slippage between said wheel and friction disk,said following means is carnmed from one set of arcuate surfaces to theother and moved axially, a circuit for energizing said motor forrotation in one direction, a circuit for enand means responsive to axialmovement of said disk for de-energizing one or the other of saidcircuits and preparing the remaining circuit for subsequentenergization.

References Cited in the file of this patent UNITED STATES PATENTSChandler July 31, 1928 Hawkins Jan. 25, 1938 Opalek Feb. 22, 1944Eddison Sept. 13, 1949 Slack Jan. 2, 1951 Hopkins et a1 Dec. 25, 1951Michie Aug. 4, 1953 Moody et a1 Sept. 15, 1953 Hahn Mar. 16, 1954

